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Microsoft Corp. is working with the OPC Foundation to enable almost any IIoT scenario using interoperability between the millions of OPC UA-compliant applications and equipment. Microsoft will enable IIoT users to connect manufacturing equipment and software with extended support of OPC UA's open-source software stack. Microsoft’s extended support for OPC UA spans its IoT offerings from local connectivity with Windows devices to cloud connectivity via Microsoft Azure. Integration with Azure IoT allows customers to easily send OPC UA data to the Azure cloud, as well as command and control OPC UA devices remotely from the Azure cloud.
Pepperl+Fuchs broke ground June 2 on its new U.S. distribution and engineering center in Katy, Texas, near…

While routine build-up and clogging in process applications is annoying, process scaling is more persistent, causes unplanned downtime and increases costs in many industries. It's typically composed of calcium carbonate, wax, grease or similar…

Just as you can't have too many friends, level measurement applications can't get enough ease of use, reliability and safety. Thanks to increasing process industry needs and user demand for them, these are the three unifying priorities that drove…

Our panel of experts explore best practices for dealing with buildup on chemical seals of a differential pressure flowmeter.

Q: We have a venturi flowmeter with 3-in. flanged pressure taps and flanged chemical seals with capillary tubes in a 44-in. vertical pipe (Figure 1). The fluid is hydrocarbon (polymeric) gas. The problem is that the chemical seal diaphragms often…

A Control Design reader writes: We have several temperature, pressure and flow sensors on a new medical-device cleaning skid that we are developing. These instruments are connected to a PLC as 4-20 mA inputs, and there is also a 4-20 mA output used to control a pump motor speed. A recent failure of a flow sensor brought the process skid instrumentation to my company's quality manager's attention. He asked how we know that the temperatures, pressure and flow are accurate, and how do we know that we are cleaning properly.
I've been tasked to write a procedure for troubleshooting, calibrating and testing the 4-20 mA instruments on the skid. I can probably stumble through this, but what are some best practices for troubleshooting the analog…

Control's Monthly Resource Guide brings you the latest online resources on a variety of process control topics.

MULTI-PART WEIGHING
This four-section webpage by Omega Engineering covers "Weighing Applications," "Weighing System Design," "Installation and Calibration" and "Specialized Installations." The whole group is located at…

FOPDT model has demonstrated utility for controller tuning rules, for structuring decouplers and feedforward control algorithms.

A first-order plus deadtime (FOPDT) model is a simple approximation of the dynamic response (the transient or time-response) of a process variable to an influence. It’s also called first-order lag plus deadtime (FOLPDT), or “deadtime” may be…

'To the degree networks and standards can provide easy, consistent and seamless access to device-resident controls, the vision of truly distributed control may finally dawn upon us.'

Every compressor in the facility went down at once that day, when a PLC redundancy switchover didn’t transfer in time. The engineers didn’t know that each P453 remote I/O processor had a dip-switch-selectable timeout setting—if it didn’t…

A Control Design reader writes: We have several temperature, pressure and flow sensors on a new medical-device cleaning skid that we are developing. These instruments are connected to a PLC as 4-20 mA inputs, and there is also a 4-20 mA output used to control a pump motor speed. A recent failure of a flow sensor brought the process skid instrumentation to my company's quality manager's attention. He asked how we know that the temperatures, pressure and flow are accurate, and how do we know that we are cleaning properly.
I've been tasked to write a procedure for troubleshooting, calibrating and testing the 4-20 mA instruments on the skid. I can probably stumble through this, but what are some best practices for troubleshooting the analog…

Most public utilities deliver basic power and water, and God bless them for doing it. However, a few go beyond their essential missions, and seek to further enhance the overall well-being and prosperity of their communities.
One of these is…

Advanced control on fuel and steam can control emissions while saving millions.

It’s no secret that advanced process control (APC) has played a major role in the process industries for many decades. However, while many organizations focus only on major process units, there’s often an untapped opportunity to do more, and…

Our readers tell us who they think delivers the best technology in our industry

There's knowledge in our readers. That's why every year we ask our loyal audience to help us determine which automation service providers offer the best products and brands they can rely on to get the best combination of performance, ease of use,…

Just when it seems like today’s sophisticated motors and drives can’t possibly add more efficiencies and capabilities, engineers conjure up new tricks and refinements, followed by end users and system integrators who materialize new settings and…

Control's monthly guide brings you invaluable industry information to stay up to date on the latest trends and developments.

THE CLASSIC VALVE BOOK
The fourth edition of the 295-page classic text, "Control Valve Handbook," by Fisher Controls International and Emerson Process Management reports this classic text has been a primary reference since its first printing in1965.

Control's monthly guide brings you invaluable industry information to stay up to date on the latest trends and developments.

THE CLASSIC VALVE BOOK
The fourth edition of the 295-page classic text, "Control Valve Handbook," by Fisher Controls International and Emerson Process Management reports this classic text has been a primary reference since its first printing in1965.

Just when it seems like today’s sophisticated motors and drives can’t possibly add more efficiencies and capabilities, engineers conjure up new tricks and refinements, followed by end users and system integrators who materialize new settings and…

Actionable information is essential for the effectiveness of the 'loop,' as it is for closed-loop control and open-loop alarms.

When I sat down in my office this morning, I was greeted by the operations manager, who pointed out an entry from last night’s operations log: “Did you see? The boiler steam vent is in manual because the pressure reading whacked out and made the…

Actionable information is essential for the effectiveness of the 'loop,' as it is for closed-loop control and open-loop alarms.

When I sat down in my office this morning, I was greeted by the operations manager, who pointed out an entry from last night’s operations log: “Did you see? The boiler steam vent is in manual because the pressure reading whacked out and made the…

Actionable information is essential for the effectiveness of the 'loop,' as it is for closed-loop control and open-loop alarms.

When I sat down in my office this morning, I was greeted by the operations manager, who pointed out an entry from last night’s operations log: “Did you see? The boiler steam vent is in manual because the pressure reading whacked out and made the…

Our readers tell us who they think delivers the best technology in our industry

There's knowledge in our readers. That's why every year we ask our loyal audience to help us determine which automation service providers offer the best products and brands they can rely on to get the best combination of performance, ease of use,…

Visualizing and contextualizing safety data can have a positive impact on productivity and compliance.

"Information is one thing, but safety information is quite another," says George Schuster. He should know. He’s charged with business development for the Global Safety Team of Rockwell Automation and has seen many plants and factories begin to…

How to deal with the constraints of putting access points in hazardous areas.

In an ideal world, it wouldn’t be necessary to worry about explosive atmospheres. Unfortunately, plant environments are far from ideal, with most process plants being about 80% Class I, Div. 2 (Zone 2) and another 10% Class I Div. 1 (Zone 1), so…

Key is to learn as much as possible to make digital technologies safe, secure and successful in process settings.

As usual, and I’m sure this is true for many of you, this year’s autumn season has been a frantic dash of work, deadlines, sleep deprivation, indigestion and suspiciously arthritic stiffness. In my case, this means covering all sides of the…

With today’s network technology, even Ethernet and wireless are almost always fast enough.

As automation professionals, one issue we have about control loops is ensuring we're able to support real-time control. Historically, when Ethernet was 10 MB/s and there were multiple drops on a single port, collisions were a significant concern and…

With today’s network technology, even Ethernet and wireless are almost always fast enough.

As automation professionals, one issue we have about control loops is ensuring we're able to support real-time control. Historically, when Ethernet was 10 MB/s and there were multiple drops on a single port, collisions were a significant concern and…

Because they're the crossroads, nexus and Grand Central Station for sensor signals and data arriving and requests and actuation instructions departing, it's a big help that I/O and terminal blocks are more flexible and capable than ever.

Compact, Remote I/O for Zone 2/Div 2
LB System remote I/O has more power in less space with high-performance, compact modules plugged into a backplane. Energy-saving power management and low-power dissipation allow maximum packing density. With the…

Be just 33 seconds more productive each hour, and the savings mount quickly.

Rockwell Automation previewed its new, forward-looking App Platform for mobility at this week’s TechED conference in Orlando. While focused first on redefining smartphone use on the plant floor – with the aim of making individual workers more…

Control’s latest State of Technology report delves into the many aspects of power systems of interest in process plants.

From sourcing and ensuring uninterrupted flows of clean electricity to monitoring, regulating and metering generation and consumption throughout a facility, process automation professionals who want a smooth-running, efficient and reliable facility are well advised to seek and control power.
This anthology of recent articles delves into the many aspects of power systems of interest in process plants. Remote and wireless systems are speeding development and standardization of energy harvesting and improved battery systems.
Line-powered supplies that used to only transform electricity and maybe offer surge protection are now monitoring and measuring current and voltage profiles, implementing alerts and alarms, and sending data up to…

Greg: Here we take advantage of the chance to talk to Bill Thomas, who provides a great lesson of how to succeed in advancing capabilities and opportunities in his career and the control systems for which he was responsible. His career and the…

Control's monthly guide brings you invaluable industry information to stay up to date on the latest trends and developments.

AT THEIR BEST, ALL THE TIME
ExperTune’s white paper, “How to Improve Performance of Process Control Assets,” by George Buckbee, P.E., describes the practice of real-time asset performance management, shows how to get assets to perform at their best all the time, and demonstrates the value of integrating these tools for a performance picture that delivers financial results. It’s available here.
ISA / www.isa.org
ANALYZING, PREDICTING PROBLEMS
This 57-minute video, “Avoid Equipment Surprises: Predictive Diagnostics for Oil & Gas,” is presented by Joe Dupree, GE Automation and Controls, and users from NiSource Gas and Alyeska. They demonstrate condition-based monitoring, predictive analytics and other tools for evaluating…

Steve Christian remembers the days—not too long ago—when production schedules were printed on sheets of paper and distributed to operators at his plant, who would manually twist valve handles to send the Ragu sauce tomato slurry from one kettle…

Advanced control on fuel and steam can control emissions while saving millions.

It’s no secret that advanced process control (APC) has played a major role in the process industries for many decades. However, while many organizations focus only on major process units, there’s often an untapped opportunity to do more, and…

Find and slay the dragons lurking in the typical safety instrumented system.

Cybersecurity is a growing concern in the process industries, and a number of good articles have been written about it for industrial control systems (ICS)—many full of doom and gloom. Here, we will divide the ICS into two parts: safety…

Big data can only help users if they understand what it is, how it can affect their controls and processes, and how they can use it to optimize operations.

Similar to any new technology emerging on the process control front, big data can only help users make better decisions if they understand what it is, how it can affect their controls and processes, and how they can use it to optimize operations.

Our readers tell us who they think delivers the best technology in our industry

There's knowledge in our readers. That's why every year we ask our loyal audience to help us determine which automation service providers offer the best products and brands they can rely on to get the best combination of performance, ease of use,…

Interface Detector for Variable Specific Gravity

This column is moderated by Béla Lipták, automation and safety consultant and editor of the Instrument and Automation Engineers' Handbook (IAEH). If you have an automation-related question for this column, write to liptakbela@aol.com.

Q: We have a horizontal vessel in which we are separating lean caustic from disulfide oil (DSO). To measure the level of the interface, we are using a differential displacer transmitter, based on the specific gravity of DSO and caustic. Due to the variation of the specific gravities of caustic and DSO, it is hard to calibrate the transmitter, and therefore, it is always out of service. Would you please help us with this problem, and tell me which kind of transmitter would be best for this application?

A: Since you have not supplied detailed information associated with the vessels, process data of minimum and maximum specific gravities, or height of interface measurement, my advice is only referential. If you have so much instability in the specific gravity and can't maintain the separation properly, then you have to analyze the possibility of using one of the following systems.

A guided-wave radar transmitter can generally detect the interface points fairly well, but the process needs to be stable enough to have a clear and well-defined interface area. If the interface is not well-defined due to turbulence, miscibility issues, etc., then you may require a stilling well or other means to create a calm area for the interface to form properly.

Another option is to use a capacitive-type level transmitter. The biggest question with this sensor is whether the measuring chamber, as well as the residence time in the vessel, are suitable for producing a well-defined interface.

Yet another option is to have two dedicated density sensors measuring the density of each of the caustic and the DSO layers, and then use their signals to modify the hydrostatic heads on the two sides of a differential pressure transmitter, so they compensate for the specific gravity changes. This method will work only in systems that are very slow, and allow for the changes to be measured and applied to the interface detector signal. This system, when it was used many years ago, required very specific calculations, and even then, if the differences between the specific gravities varied too much, it could still cause errors.

My suggestion would be that you contact companies like Endress+Hauser, Rosemount, AGAR, Honeywell, ABB, etc.

A: The dielectric constant of disulphide oil (RSSR) is on the order of 6 to 7.5, and it will be floating on the dilute NaOH. The dielectric constant of the latter is more difficult to determine, but it should be above 20. This makes guided-wave radar a reasonable candidate. The same transmitter can give both level and interface, provided the thickness of the disulphide oil is more than 100 to 150 mm. If you can access the vessel internals, one of the usual vendors (Emerson, Magnetrol, etc.) will likely be able to check the feasibility for you. The level/interface signal relies on the existence of a sufficient difference in dielectric constant to reflect the signal, rather than an absolute knowledge of the value.

Trying to use an existing external displacer chamber is of doubtful utility, as you need tappings in all three phases at all times for the levels in the external chamber to match those inside the vessel (a common source of failure of density-type measurements).

A: When you are asking for help on these matters you should always give the necessary process conditions (e.g., pressure and temperature range, density, etc.).

I am thinking that this could be an ideal application for guided-wave radar (GWR) level, but without knowing the process conditions, it's always hard to be definitive.

In this case, the density is important because it will not work if the caustic is the less dense material and is the top layer. So I'm hoping that DSO is less dense and has a very low dielectric constant.If the top layer has a high dielectric constant, you'll measure the top of that layer and not the interface. Also, there are temperature and pressure limits on the GWR.

On the other hand, GWR will not work when the caustic is the top layer. Similarly, a capacitance probe will give you the thickness of the caustic layer, but only if it's always on the top or bottom.

The GWR Solution

Figure 1. Guided-wave radar may be the simplest solution to this measurement problem. The sensor on the left is from Magnetrol. The one on the right is from Emerson.

I believe that you have a bigger problem than level measurement. I suspect you have a separator of some sort, but if the two materials are so close in density and also vary (one moment one is denser and at another moment, another is denser), then I think you have some serious process problems.

A level profiler would probably work in providing a complete profile. However, these instruments are very expensive (several hundred thousand dollars).

I think that your team musthas to go back to basics and really understand what needs to happen from a fundamental process design. There is not enough information on the design to say what is needed. The level profiler will most likely work, but I suspect that a level measurement may not be what is required.

A: Measuring the interface in a separator requires that the top layer always be lighter than the bottom one. If that is not the case, the separation will not occur, and it is the process itself that needs to be fixed, not the selection of the interface detector.

Assuming that the separator is properly designed and separation does occur, the interface can be detected even if the specific gravity of one or both layers varies. Naturally, in that case, one should not use interface detectors that depend for their operation on density (DP, float, displacement), but should use a property of the two layers that is both constant and different. These include electric or thermal conductivity, opacity, sonic/ultrasonic transmittance, radar (electromagnetic waves), microwaves, etc.

In your case, probably the simplest and least expensive solution is guided-wave radar, which can be coaxial, single- or twin-element. The single-element design is the least sensitive, but the most forgiving in case of coating. GWR measures both the total and the interface levels, and is unaffected by specific gravity variations. Operation involves sending a radar pulse down the guide, which will be partially reflected by the total level, but some of the remaining energy continues down and will be reflected by the interface with the higher dielectric layer (Figure 1). Naturally, it is critically important that the dielectric constant of the upper layer be less than 5, and the dielectric constant of the bottom layer be greater than 15.